Jamie McCombe is out for at least two months after it was revealed that the defender has played with a stress fracture of the back for more than a year.
McCombe got 45 minutes under his belt in the pre-season win at Rossington Main earlier this month and had hoped to be fit for the start of the season.
But with little sign of the injury improving, the 30-year-old centre back has been ordered to take time out to get the problem fixed.
“Jamie’s having problems with his back. He’ll be out for two to three months,” said boss Paul Dickov.
“It’s a long-standing injury he’s got and to be fair to Jamie he’s tried to play through it the last season or two.
“But when he came in and we had a look at it we decided it’s better for him to get it fixed.
“He’ll be in a cast for a few weeks and we’ll be lucky if he’s back within two months.
“He’s had a stress fracture of his back since his Huddersfield days which he’s managed to play through,” he added.
“But if you manage injuries for that long it’s difficult to do yourself justice.
“Jamie’s done fantastically well to play last season but we feel as a staff that we’re better getting him one hundred per cent fit.
“If he misses two months he’s still got eight months of the season to look forward to.”
McCombe’s absence places a question mark over who will partner Rob Jones at the heart of Doncaster’s defence in this weekend’s Championship opener with Blackpool, although makeshift centre back Tommy Spurr is expected to finally put pen to paper this week.
Dickov is mulling over a formal approach for Spurs defender Bongani Khumalo, who played in Saturday’s 2-1 friemdly win over Bradford City.
If, as expected, his transfer kitty is boosted by funds from the Irish consortium currently in talks with the club, Dickov is expected to step up his pursuit of out of favour Norwich centre back Leon Barnett.